1. Field
The presently disclosed subject matter relates to vehicle headlights using a semiconductor light source, and more particularly to vehicle headlights with a simple structure that can provide a favorable light distribution pattern to illuminate an overhead sign area in addition to a light distribution pattern used as a low beam for a headlight by using the semiconductor light source.
2. Description of the Related Art
Recently, vehicle headlights using an LED light source, which may provide a light distribution pattern to illuminate an overhead sign area where traffic signs, road signs and the like are located, have been developed. A conventional vehicle headlight shown in FIG. 7a, which is a cross-sectional view showing a vehicle lamp capable of forming a light distribution pattern toward the overhead sign area, is disclosed in Patent document No. 1 (Japanese Patent Application Laid Open JP2010-277818).
The vehicle lamp 200 includes an LED light source 210, a projector lens 220 located in a direction toward a light-emission of the LED light source 210, and a reflector 230 located in an upward direction of the LED light source 210 and the projector lens 220, reflecting the emitted from the LED light source 210 in a forward and obliquely upward direction of the LED light source 210 and thereby forming a light distribution pattern for an overhead sign area.
FIG. 7b is an exemplary light distribution pattern formed by the vehicle lamp 200, wherein H-H shows a horizontal line and V-V shows a vertical line in a direction toward a light-emission of the vehicle lamp 200. The exemplary light distribution pattern may include a basic light distribution pattern Pa, which is located under the horizontal line H-H so as to extend in the horizontal direction with reference to the vertical line V-V. Accordingly, the basic light distribution pattern Pa may be used as a low beam for a headlight.
In addition, the light distribution pattern projected by the vehicle lamp 200 may include a light distribution pattern Pb, which is formed using the light reflected in the forward and obliquely upward direction of the LED light source 210 by the reflector 230. The light distribution pattern Pb may be directed toward the overhead sign area, and therefore may be used as a light distribution for the overhead sign area.
As described above, the vehicle lamp 200 may provide the basic light distribution pattern Pa and the light distribution pattern Pb, which may illuminate toward the overhead sign area using the above-described structure including an additional reflector. However, such a structure must include the additional reflector 230 for the light distribution pattern Pb, and therefore may always cause problems such that headlights based upon the structure may increase in size and area, and also may be subject to complex structure due to additional parts.
The above-referenced Patent Documents and additional Patent Documents are listed below and are hereby incorporated with their English abstracts and specification in their entireties.    1. Patent document No. 1: Japanese Patent Application Laid Open JP2010-277818    2. Patent document No. 2: U.S. patent application Ser. No. 13/229,663 published as U.S. Patent Publication No. US2012/0235169A1    3. Patent document No. 3: U.S. patent application Ser. No. 12/874,361 published as U.S. Patent Publication No. US 2011-0051446 A1    4. Patent document No. 4: U.S. patent application Ser. No. 12/876,073 published as U.S. Patent Publication No. US 2011-0051448 A1    5. Patent document No. 5: U.S. Divisional patent application (Parent U.S. patent application Ser. No. 12/720,819, U.S. Pat. No. 8,251,560)    6. Patent Document No. 6: U.S. Patent Publication No. 2012-0320617 A1
The disclosed subject matter has been devised to consider the above and other problems, characteristics and features. Thus, an embodiment of the disclosed subject matter can include a vehicle headlight using a semiconductor light source with a simple structure that can form a basic light distribution pattern used as a low beam and a light distribution pattern for an overhead sign area without a reflector. In this case, the vehicle headlight can be constructed from a single projector type headlight that can be formed in a small size, and also can provide a favorable light distribution pattern for the overhead sign area, which can inhibit the color separation and can provide a high level of visibility to drivers and pedestrians. Thus, the vehicle headlight can result in an increase in the possible range of headlight design, and therefore can be employed for various vehicles including a small size car.